Vibrator



Feb. 21, 1939. H. M DRESSEL 2,148,193

VIBRATOR Filed NOV. l, 1937 T? a5 W 0 W 3 hv j? wm um il@ l m// n'-515 l l i Patented Feb. 21, 1939 UNITED STATES VIBRATOR Henry M. Drossel, Chicago, Ill., assignor to Oak Manufacturing Company, Chicago, lll., a corporation of Illinois Application November 1, 1937, Serial No. 172,177

7 Claims.

This invention relates to vibrators and particularly to a means for insuring substantially arcless operation of vibrators. In my prior Patent 2,012,123, granted August 20, 1935, I have disclosed the use of a short-circuited winding, preferably wound in bifilar relationship to the vibrator winding for the purpose of reducing arcing at the driving contacts. As pointed out in that patent, it is desirable to separate the driving contacts from the power contacts for the reason that the driving contacts which handle but little power may be made of high grade material. The power contacts which control the transformer circuit are customarily larger and heavier and may be of cheaper material.

The invention herein disclosed has the same general object as the above patent and accomplishes the same by different means.

Referring to the drawing:

Figure 1 shows a circuit diagram of one form of the invention, while Figure 2 shows a circuit diagram of the modification thereof.

Referring to Figure l, the vibrator, which may be of any desired construction and preferably like that shown in the co-pending application of Dressel et al., Serial No. 758,925, filed December 9, 1935. The vibrator comprises a reed I rigidly fastened at one end and having an armature at the free end and adapted to cause the reed to vibrate in response to the fluctuating magnetic eld created in pole piece I2. Reed I0 carries a, vibrator driving contact I5 which is adapted to cooperate with a xed driving contact I6 preferably mounted on a spring I1 so that-a yielding of the contact will occur.

Reed I0 also carries a pair of vibratory power contacts and 2l cooperating with fixed power contacts 22 and 23 respectively. These fixed contacts may be connected to a transformer primary in the usual fashion.

In order to excite pole piece I2, a magnetizing coil is provided having one terminal 3| connected by a lead 32 to fixed driving contact I6. The other terminal 33 of coil 30 is connected through a junction point 34 to a line 35 which runs to one terminal of a battery 36 whose other terminal is connected to reed I0.

As is well understood, reed I0 is vibrated back and forth and as shown in Figure 1 is adapted to swing far enough to the right so that fixed contacts 20 and 22 engage. Fixed driving contact I6 is adapted to engage movable contact |5 in the normal rest position of the device to be self starting.

In order to reduce arcing across driving conthe reed to enable tacts I5 and I6 of the vibrator, I preferably provide a second winding 40 having one terminal 4| connected by line 42 back to junction point 34 while the other terminal 43tis connected by line 44 back to line 32. It is thus evident that the magnetic effect of second winding 40 opposes that of winding 30. Winding 40vis preferably wound in bifilar relationship to winding 30 and has a comparatively high resistance to that of winding 30. Thus, inactual practice, a vibrator for use in connection with automobile radios on six volts generally has a` magnetizing coil having a resistance of about l2 ohms. In accordance with this invention, the second winding will preierably have a resistance of at least about 48 ohms. This resistance could be obtained by either using copper wire of a suitable gauge or by using a metal having more resistance than copper and adjusting the gauge accordingly. The resistance in this case may be anywheres from 4 to 25 times as much as the magnetizing coil. It is understood of course that the magnetizing effect of coil 40 on the reed is substantially less than that of coil 30.

As is clearly evident from the circuit diagram, the second coil 40 is connected directly across the terminals of the .magnetizing coil. When the driving contacts open, the current in the coils of the magnetizing winding has a gradual resistance decay characteristic.

It is obvious that if the second winding is closely coupled to the rst winding, but a small current should pass through when the driving contacts are closed. On the other hand, too high a resistance will prevent the magnetizing winding from discharging readily and thus defeat the object of the invention, namely the elimination of sparking at the driving contacts. I have determined that the above proportions are most desirable. It isunderstood, of course, that under special cases, the proportion may be varied.

Referring to Figure 2, the reed ||0 is provided with armature cooperating with a magnetizing pole ||2, The cooperating driving contacts I I5 and l I6 are similar to that shown in Figure l. Driving contact IIS is spring supported at Power contacts |20 and |2| are carried by the reed and cooperate with fixed power contacts |22 and |23, The magnetizing winding |30 has its terminal |3| connected by a line |32 back to driving contact IIS, while the other terminal |33 is connected through a junction point |34 to line and thence through the battery |36 back to reed 0.

Connected to junction |34 is one terminal |40 of a second winding 4| whose other terminal |42 is connected to terminal |43 of a third winding |44 whose remaining terminal |45 is connected by line |46 back to line |32. Windings |4| and |44 are preferably though not necessarily of higher resistance than magnetizing winding |30. These two windings are preferably wound in bifilar relationship and, as clearly indicated, have equal and opposite magnetizing eirects. Both of these two additional windings may be wound in bilar relationship to the main magnetizing winding |30, although this is not essential. Since the two additional windings neutralize each other, it is' clear that no demagnetizing action of the energizing current need be feared. However, in order not to waste power, it is desirable to have these two additional windings IBI and |44 of substantially higher resistance than winding |30, such as, for example, between 4 and 25 times, as disclosed above in connection with Figure 1.

What is claimed is:

1. In a vibrator having a reed provided with a free vibrator end and a magnetizable pole piece, a contact carried by said reed and movable therewith, a stationary contact cooperating with said movable contact, a magnetizing coil for saidv pole piece connected to said two contacts for effecting reed vibration on circuit energization and an auxiliary winding disposed in electromagnetic relationship to said magnetizing winding and connected directly in shunt with said magnetizing winding but in reversed relation, said auxiliary winding having a substantially smaller magnetic effect on the reed than said magnetizing winding.

2. The structure of claim 1 wherein said auxiliary winding is wound in bilar relationship with the magnetizing winding.

3. The vibrator of claim 1 wherein said reed aisance carries 'additional power contacts .and wherein nections between said magnetizing coil and' said contacts for eecting reed vibration upon circuit energization, and a pair of auxiliary windings in series with each other but in shunt to said magnetizing winding for suppressing arcing at the contacts, said auxiliary windings having equal and opposite magnetic eii'ects on said pole piece.

5. The vibrator of claim 4 wherein said auxiliary windings are wound in bilar relation to each other.

6. The vibrator of claim 4 wherein said auxiliary windings and magnetizing winding are all wound in bifllar relationship to provide maximum coupling.

7. In a vibrator having a reed provided with a free vibrator end and a magnetizable pole piece, a contact carried by said reed and movable therewith, a stationary contact cooperating with said movable contact, a magnetizing coil for said pole piece connected to said two contacts for eiecting reed vibration upon circuit energization and an auxiliary winding in electromagnetic relationship to said magnetizing winding and shunted across said magnetizing winding, said auxiliary windingl having at least one portion thereof in reversedrelationship to said magnetizing winding, with the magnetic effect of said reversed portion on said reed being less than the magnetic effect of said magnetizing winding on said reed.

HENRY M. DRESSEL. 

